Pump dispenser for delivering a predetermined dosage regardless of method of actuation

Abstract

A finger operated pump dispenser employing interconnected upper and lower cylinders, first and second pistons disposed in the upper and lower cylinders, a hollow sleeve, and a stem which extends upwardly through the first piston into the sleeve. The first cylinder, the stem and the two pistons define a pump chamber which is filled with fluid. When the dispenser is actuated, fluid is displaced from the chamber into the second cylinder and a port is opened. The port can be made to open at the moment that all of the fluid is displaced into the second cylinder. Once the port is opened, the fluid is discharged and further piston movement enables fluid to be pulled upward out of the container secured to the dispenser via an opening formed between the second piston, stem and inner wall of the second cylinder refilling the chamber. The motions of pistons, stem and sleeve are so controlled that accurate dosage is produced independently of the method of actuation.

What is claimed is: 
     
       1. A finger actuated pump dispenser mounted on a fluid containing vessel which when actuated will discharge fluid at a predetermined pressure and will deliver a predetermined dosage regardless of the method of actuation, the dispenser comprising: a vertical hollow elongated body having an upper section defining a first hollow vertical cylinder with a first diameter and open upper end and an integral lower section defining a second hollow vertical cylinder with a second and smaller diameter and a closed lower end with a central opening, the lower end of the first cylinder being joined to an open upper end of the second cylinder, the body having a first vertical bore extending through both cylinders;   a collar having a central opening aligned with the first bore and enclosing the upper end of the first cylinder;   a sleeve open at upper and lower ends and having a first enlargement intermediate these ends, the sleeve having a second vertical bore aligned with the first bore, the portion of the sleeve intermediate the upper end and the first enlargement extending upwardly through the collar opening with the first enlargement being disposed below the collar, the first enlargement and the remaining portion of the sleeve being disposed within the first cylinder;   a first hollow vertical piston having an upper open end and a lower closed end having a central opening which is aligned with the first bore, the first piston being disposed and vertically slidable along the sleeve within the first cylinder;   a vertical stem having an upper vertical section with relatively small cross sectional area which extends upwardly through the first piston and through the second bore, the upper section being spaced inwardly from the second bore, the space between the upper section and the inner wall of the second bore defining a fluid discharge path, the stem having an integral lower vertical section with a cross sectional area which is larger than that of the upper section and smaller than that of the second cylinder, the upper end of the lower section being adjacent the lower end of the first piston;   a second vertical piston vertically slidable in the second cylinder with an upper end adjacent and engagable with the lower end of the lower section, the second piston having a second enlargement intermediate its ends which engages the inner wall of the second cylinder;   first spring means disposed within the first cylinder between the lower end of the first piston and the first enlargement;   second spring means disposed within the second cylinder between the lower end of the second cylinder and the second enlargement; and   means associated with the second piston and the second cylinder and actuated during at a selected position of the second piston with respect to the second cylinder during an upstroke to establish a fluid transfer path between the fluid in the container and a pump chamber formed by the space subtended by the inner wall of the first cylinder, the stem and the two pistons.   
     
     
       2. The dispenser of claim 1 wherein the means associated with the second piston and cylinder includes an enlarged recess disposed in the inner wall of the second cylinder at its upper end, said fluid transfer path being established when the second enlargement is aligned with and spaced from said recess. 
     
     
       3. The dispenser of claim 2 further including actuator means connected to the upper end of the upper stem section and the upper end of the sleeve. 
     
     
       4. The dispenser of claim 3 wherein the lower end of the first cylinder has a horizontal groove adjacent the upper end of the second cylinder, the lower end of the first piston being engagable with said groove. 
     
     
       5. The dispenser of claim 3 wherein the first piston and the stem cooperate to define a port which when open permits fluid to be discharged through the fluid discharge port and when closed blocks the discharge of fluid, the port being closed when the lower end of the first piston engages the upper end of the lower stem section of the stem and being closed when the lower end of the first piston is spaced from the upper end of the lower stem section. 
     
     
       6. The dispenser of claim 5 wherein the upper end of the lower stem section has a horizontal recess and the lower end of the first piston has a downwardly extending inner ring, the port being closed when the ring engages the recess and being open when the ring is spaced from the recess. 
     
     
       7. The dispenser of claim 5 wherein the lower stem section has a vertical recess and the upper end of the second piston extends into the recess when the second piston engages the lower end of the lower stem section. 
     
     
       8. The dispenser of claim 7 wherein the upper stem section is solid and the lower stem section is hollow. 
     
     
       9. The dispenser of claim 8 wherein the second enlargement has an upper surface with a horizontal groove and the lower end of the lower stem section has a ring which engages the horizontal groove when the second piston engages the lower end of the lower stem section. 
     
     
       10. The dispenser of claim 9 wherein the central opening in the lower end of the second cylinder is disposed above the remainder of the lower end, the downward movement of the second piston being limited at the position at which the lower end of the second piston engages the central opening. 
     
     
       11. A finger actuated pump dispenser mounted on a fluid containing vessel which when actuated will discharge fluid at a predetermined pressure and will deliver a predetermined dosage regardless of the method of actuation, the dispenser comprising: a vertical hollow elongated body having an upper section defining a first hollow vertical cylinder with a first diameter and open upper end and an integral lower section defining a second hollow vertical cylinder with a second and smaller diameter and a closed lower end with a central opening, the lower end of the first cylinder being joined to an open upper end of the second cylinder, the body having a first vertical bore extending through both cylinders;   a collar having a central opening aligned with the first bore and enclosing the upper end of the first cylinder;   a sleeve open at upper and lower ends and having a first enlargement intermediate these ends, the sleeve having a second vertical bore aligned with the first bore, the portion of the sleeve intermediate the upper end and the first enlargement extending upwardly through the collar opening with the first enlargement being disposed below the collar, the first enlargement and the remaining portion of the sleeve being disposed within the first cylinder;   a first hollow vertical piston having an upper open end and a lower closed end having a central opening which is aligned with the first bore, the first piston being disposed and vertically slidable along the sleeve within the first cylinder;   a vertical stem having an upper vertical section with relatively small cross sectional area which extends upwardly through the first piston and through the second bore, the upper section being spaced inwardly from the second bore, the space between the upper section and the inner wall of the second bore defining a fluid discharge path, the stem having an integral lower vertical section with a cross sectional area which is larger than that of the upper section and smaller than that of the second cylinder, the upper end of the lower section being adjacent the lower end of the first piston;   a second vertical piston vertically slidable in the second cylinder with an upper end adjacent and engagable with the lower end of the lower section, the second piston having a second enlargement intermediate its ends which engages the inner wall of the second cylinder;   first spring means disposed within the first cylinder between the lower end of the first piston and the first enlargement;   second spring means disposed within the second cylinder between the lower end of the second cylinder and the second enlargement; and means associated with the second piston and the second cylinder and actuated during at a selected position of the second piston with respect to the second cylinder during an upstroke to establish a fluid transfer path between the fluid in the container and a pump chamber formed by the space subtended by the inner wall of the first cylinder, the stem and the two pistons, said means associated with the second piston and cylinder including an enlarged recess disposed in the inner wall of the second cylinder at its upper end, said fluid transfer path being established when the second enlargement is aligned with and spaced from said recess; and actuator means connected to the upper end of the upper stem section and the upper end of the sleeve.